Lubricating oil compositions



3,074,885 Patented Jan.'22, 1963 1 Claim. (Cl. 252--33.6)

The'present ap'plicationis 'a division of application Serial No. 858,311, filedDe'cember 9, 4959, now Patent No. 3,028,411.

This invention relates as indicated to lubricating oil compositions and has particular reference to lubricating oils and greases containing the alkali metal salts of glycol monoborates as anti-corrosion and anti-sludging agents.

Sodium and potassium salts of various glycol monoborates have been known to those skilled in the art for a long time. However, these materials have found little or no use in industry due to the fact that methods for obtaining the salts in substantially pureform'have been costly, inefiicient and diiiicult. Consequerttly, the salts of glycol monoborates have not been exploited and their Valuable properties "havegone unknown to industry.

We'have foundthat the alkali metal salts of glycol monoborates have unique solubilities and other properties whichrna'ke them particularly desirable as additives in a number of organic media. For instance, these salts impart alkalinity and are eifective as anti-corrosion agents in lubricating greases. We have found that the salts of the glycol monoborates when added to lubricating oils act as anti-sludging agents. The salts of the glycol monoborates when added to paints, varnishes and lacquers that have organic solvents as the vehicle increase the flame resistance of said paints, varnishes and lacquers. When the glycol monoborate salts are dissolved in an organic solvent they can be used to impregnate wood and fiberboard and act as a flame retardant. When added to siloxane resins the salts of the glycol monoborates act as dehydrating and curing agents and impart the property of coating articles with the siloxane resin with a minimum of run-off and without changing the thermal stability, dielectrical properties and flexibility of the resins.

It is therefore an object of this invention to provide a method for making the alkali metal salts of glycol monoborates, which method is economically desirable and provides good yields of substantially pure salts.

It is a further object of this invention to provide compositions of lubricating oils and greases with the alkali metal salts of glycol monoborates.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention then comprises the features hereinafter fully described and pointed out in the claim, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the many ways in which the principle of the invention may be employed.

The method of making the alkali metal salts of glycol monoborates used in the lubricating oils and greases comprises reacting an alkali metal hydroxide with a diglycol boric anhydride, said di-glycol boric anhydride having the general formula:

R B-O-B R 0 0 where R is a material selected from the group consisting 2 0f; ,2 and l', 3-gly cols having'from 2-410carbon-at'orris.

While in the following example'only 'di-(2-methylpentanediol-2,4)boric anhydride is used for illustrative purposes, it will 'be"clearly 'understood that itis'only 'necessary'to rnerely'substitute in its stead any of the other defined; di-glycol boric' anhydrides to 'achieve can parable results. It is to beclearly understood that in the specification and claims the:- term glycol referes to all diols andin the present spec'ification we-are concerned with the 1,2'a'nd 1,3-diols. I

Thus the'following'rnaterials are typical examples or the 1,2 and 1,3-gly'col :boricanhydrides applicable to the present process:

Di-(propanediol 1,2)boric anhydride Dibutanediol- 1,2 boric anhydride 1 Di-(butane'dio'l l,3 boric anhydride 7 v i p n 1 Di,-(2,2,4-trimethylpentanediol-1,3 boric anhydride Di-(pentanediol-2 ,3 )boric anhydride Di-(2,3,4-trimethylpehtanediol-ZA)boric anhydride Di-(catechoDboric anhydride I Di- 2-methylpentanediol-2,4) boric' anhydride Into a two-liter, three-necked, round-bottomed flask equipped with a paddle-type stirrer, a water condenser, and a pot thermometer, were added 270 grams of di-(Z- methylpentanediol-2,4)boric anhydride and 500 mls. of

methanol; 80 grams of sodium hydroxide was then added to the liquid mixture. When the initial exothermic reaction subsided, heat was applied and the reaction mixturewas refluxed for about one-half hour. The methanol and Water of reaction were stripped from the flask and the residue, sodium 2-methylpentanediol-2,4 monoborate,

"was then removed and vacuum dried for about 2 to 4 hours. Chemical analysis of the resultant sodium 2- methylpentanediol-2,4 monoborate revealed the following data:

Na 13.76% (theory 13.86%) B 6.44% (theory 6.52%)

Essentially the same porcedure was followed in experiments using the other alkali metal hydroxides. Using lithium hydroxide, the final product of the reaction was lithium 2-methylpentanediol-2,4 monoborate whose chemical analysis revealed the following data:

Li 4.61% (theory 4.68%) B 7.12% (theory 7.22%)

Using potassium hydroxide, the final product was potassium 2-methylpentanediol-2,4 monoborate whose chemical analysis revealed the following data:

K 21.18% (theory 21.47%)

B 5.85% (theory 5.94%)

in amounts from about 0.1 to about 3% by weight, they act as an excellent anti-sludging agent, and when added in amounts from about 0.1% to about 3% to lubricating oils and greases they act as an anti-corrosion agent. It is generally accepted by those skilled in the art that metal salts of organic compounds are substantially insoluble in organic solvents. The present alkali metal glycol monoborates, however, show remarkable solubilities in many organic solvents. For example, when sodium 2-methylpentanediol-2,4 monoborate is added in amounts of from about 0.5 to about 10% to oil base paints, lacquers and varnishes, which contain common commercial solvents, all the sodium 2-methylpentanediol-2,4 monoborate dissolves and imparts the property of fiame resistance to the various paints, lacquers and varnishes. Sodium 2-methylpentanediol-2,4 monoborate when dissolved in an organic solvent such as hexane in amounts from about 0.2 to about 10% can be used to impregnate wood and fiberboard for increased fire retardance.

A very serious condition that has long plagued the silicone resin industry has been the large amount of run-01f of a silicone resin from a coated article while the resin was curing. The electrical industry has long been dipping electric coils and other articles into a solution of silicone resins, air drying and then curing the material in an oven. The run-ofl at times has been over 50% of the resin and when the resin gels in the bottom of the curing oven it is of course of no further value. We have found that additions of from about 0.1 to about 4% of one of the present alkali metal salts of glycol monoborate to many of the silicone resin solutions has lowered the runoif to less than about 20% with no curing catalyst added.

Even more outstanding results are obtained when from about 0.1 to about 4% of sodium 2-methy1pentanediol-2,4 monoborate is added as a dehydrating agent to a silicone resin which contains as little as 0.05% of one of the wellknown silicone curing catalysts, such as zinc hexoate, zinc 'octoate, lead butytrate or cobalt naphthenate. In this instance the run-off is substantially eliminated.

Other modes of applying the principle of the invention may be employed provided the features stated in the following claim or the equivalent of such be employed.

We, therefore, particularly point out and claim as our invention:

A composition of matter consisting essentially of a major proportion of a hydrocarbon lubricating oil and from about 0.1 to about 3% of an anti-sludging and anti-corrosion agent, said agent selected from the group consisting of the alkali metal salts of the 1,2 and 1,3 glycol monoborates, having the general formula:

where R is a material selected from the group of 1,2 and 1,3 alkylene radicals having from 2 to '10 carbon atoms and M is an alkali metal References Cited in the file of this patent UNITED STATES PATENTS 2,040,997 Johnson May 19, 1936 2,312,208 Clayton et a1 Feb. 23, 1943 2,497,521 Trautman Feb. 14, 1950 2,979,524 Wright et al, Apr. 11, 1961 

